Most appear to be made in China and are (hopefully) genuine casino/hotel gift shop items. I'd guess every large casino has them, and in various designs/colors/etc. If I can pick 'em up for a buck apiece at swap meets, I'm happy. Somewhere out there must be a "keychain collectors club" with some folks also interested in such trivia. Or, is that us?

Best buying strategy for key fobs: try to hit up the sellers toward the end of the swap, when they are happy to unload what they can. For chips - maybe buy earlier, lest they get snapped up by someone else - or boxed away (chips always sink to the bottom of the box).